Disable requirement for media notifications to be enabled to hide ARC media notifications

This will allow blocking when the media notifications are turned off but the new CrOS media
controls are enabled.

BUG=1142628

Change-Id: Ic35586c508c7c173c2ed828ff6697c841f9a6c84
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2625690
Auto-Submit: Becca Hughes <beccahughes@chromium.org>
Reviewed-by: Tommy Steimel <steimel@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842726}

ash/public/cpp/ash_features.cc

@@ -187,8 +187,7 @@ bool IsFullRestoreEnabled() {
 }
 
 bool IsHideArcMediaNotificationsEnabled() {
-  return base::FeatureList::IsEnabled(kMediaSessionNotification) &&
-         base::FeatureList::IsEnabled(kHideArcMediaNotifications);
+  return base::FeatureList::IsEnabled(kHideArcMediaNotifications);
 }
 
 bool IsKeyboardBasedDisplayArrangementInSettingsEnabled() {